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McPheron MA, Felker MV. Clinical perspectives: Treating spinal muscular atrophy. Mol Ther 2024:S1525-0016(24)00402-7. [PMID: 38894541 DOI: 10.1016/j.ymthe.2024.06.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 04/26/2024] [Accepted: 06/14/2024] [Indexed: 06/21/2024] Open
Abstract
Spinal muscular atrophy is a rare and progressive neuromuscular disease that, without treatment, leads to progressive weakness and often death. A plethora of studies have led to the approval of three high-cost and effective treatments since 2016. These treatments, nusinersen, onasemnogene abeparvovec, and risdiplam, have not been directly compared and have varying challenges in administration. In this review, we discuss the evidence supporting the use of these medications, the process of treatment selection, monitoring after treatment, the limited data comparing treatments, as well as future directions for investigation and therapy.
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Affiliation(s)
- Molly A McPheron
- Department of Medical and Molecular Genetics, Indiana University, Indianapolis, IN 46202, USA
| | - Marcia V Felker
- Department of Neurology, Indiana University, Indianapolis, IN 46202, USA.
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Signoria I, van der Pol WL, Groen EJN. Innovating spinal muscular atrophy models in the therapeutic era. Dis Model Mech 2023; 16:dmm050352. [PMID: 37787662 PMCID: PMC10565113 DOI: 10.1242/dmm.050352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/04/2023] Open
Abstract
Spinal muscular atrophy (SMA) is a severe, monogenetic, neuromuscular disease. A thorough understanding of its genetic cause and the availability of robust models has led to the development and approval of three gene-targeting therapies. This is a unique and exciting development for the field of neuromuscular diseases, many of which remain untreatable. The development of therapies for SMA not only opens the door to future therapeutic possibilities for other genetic neuromuscular diseases, but also informs us about the limitations of such treatments. For example, treatment response varies widely and, for many patients, significant disability remains. Currently available SMA models best recapitulate the severe types of SMA, and these models are genetically and phenotypically more homogeneous than patients. Furthermore, treating patients is leading to a shift in phenotypes with increased variability in SMA clinical presentation. Therefore, there is a need to generate model systems that better reflect these developments. Here, we will first discuss current animal models of SMA and their limitations. Next, we will discuss the characteristics required to future-proof models to assist the field in the development of additional, novel therapies for SMA.
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Affiliation(s)
- Ilaria Signoria
- Department of Neurology and Neurosurgery, UMC Utrecht Brain Center, University Medical Center Utrecht, 3584 CX Utrecht, the Netherlands
| | - W. Ludo van der Pol
- Department of Neurology and Neurosurgery, UMC Utrecht Brain Center, University Medical Center Utrecht, 3584 CX Utrecht, the Netherlands
| | - Ewout J. N. Groen
- Department of Neurology and Neurosurgery, UMC Utrecht Brain Center, University Medical Center Utrecht, 3584 CX Utrecht, the Netherlands
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Chehade L, Deguise MO, De Repentigny Y, Yaworski R, Beauvais A, Gagnon S, Hensel N, Kothary R. Suppression of the necroptotic cell death pathways improves survival in Smn2B/− mice. Front Cell Neurosci 2022; 16:972029. [PMID: 35990890 PMCID: PMC9381707 DOI: 10.3389/fncel.2022.972029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Accepted: 07/11/2022] [Indexed: 11/13/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a monogenic neuromuscular disease caused by low levels of the Survival Motor Neuron (SMN) protein. Motor neuron degeneration is the central hallmark of the disease. However, the SMN protein is ubiquitously expressed and depletion of the protein in peripheral tissues results in intrinsic disease manifestations, including muscle defects, independent of neurodegeneration. The approved SMN-restoring therapies have led to remarkable clinical improvements in SMA patients. Yet, the presence of a significant number of non-responders stresses the need for complementary therapeutic strategies targeting processes which do not rely solely on restoring SMN. Dysregulated cell death pathways are candidates for SMN-independent pathomechanisms in SMA. Receptor-interacting protein kinase 1 (RIPK1) and RIPK3 have been widely recognized as critical therapeutic targets of necroptosis, an important form of programmed cell death. In addition, Caspase-1 plays a fundamental role in inflammation and cell death. In this study, we evaluate the role of necroptosis, particularly RIPK3 and Caspase-1, in the Smn2B/− mouse model of SMA. We have generated a triple mutant (TKO), the Smn2B/−; Ripk3−/−; Casp1−/− mouse. TKO mice displayed a robust increase in survival and improved motor function compared to Smn2B/− mice. While there was no protection against motor neuron loss or neuromuscular junction pathology, larger muscle fibers were observed in TKO mice compared to Smn2B/− mice. Our study shows that necroptosis modulates survival, motor behavior and muscle fiber size independent of SMN levels and independent of neurodegeneration. Thus, small-molecule inhibitors of necroptosis as a combinatorial approach together with SMN-restoring drugs could be a future strategy for the treatment of SMA.
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Affiliation(s)
- Lucia Chehade
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
- Center for Neuromuscular Disease, University of Ottawa, Ottawa, ON, Canada
| | - Marc-Olivier Deguise
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
- Center for Neuromuscular Disease, University of Ottawa, Ottawa, ON, Canada
- Department of Pediatrics, Children's Hospital of Eastern Ontario, Ottawa, ON, Canada
| | - Yves De Repentigny
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada
| | - Rebecca Yaworski
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada
| | - Ariane Beauvais
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada
| | - Sabrina Gagnon
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada
| | - Niko Hensel
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada
| | - Rashmi Kothary
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
- Center for Neuromuscular Disease, University of Ottawa, Ottawa, ON, Canada
- Department of Medicine, University of Ottawa, Ottawa, ON, Canada
- Department of Biochemistry, Microbiology, and Immunology, University of Ottawa, Ottawa, ON, Canada
- *Correspondence: Rashmi Kothary
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